16 REPORT—1857. 
rent through an exhausted tube of great length and diameter, and to those exhibited 
by the beautiful arrangement known as Gassiot’s Cascade, which, with other pheno- 
mena of electrical light, were developed by this apparatus with a splendour perhaps 
never before equalled. 
Researches on the Correlation of Dynamic Electricity and the other Physical 
Forces. By M. Louis Sorer. 
INTRODUCTION. 
Suppose an electric circuit composed, for example, of a voltaic battery, the poles 
of which are united by a conductor. Suppose, in the first place, that all parts of 
this circuit are sufficiently distant from any other conducting or magnetic body, that 
the current cannot exert any exterior action. The facts may then be represented in 
the following manner. In the battery, a chemical action, the primary source of force, 
is set up. If the two poles be disunited, the chemical action can nevertheless take 
place; this production of force is manifested by heat evolved in the battery itself. If 
the poles be united by a conductor, a part of this force is converted into electricity ; 
it manifests itself without the battery in the conductor, where it again becomes trans- 
formed into heat. According to M. De la Rive and M. Favre, the sum of the quan- 
tities of heat disengaged in the battery and in the rest of the circuit, has a constant 
value for the same amount of chemical action, a law which is perfectly in accordance 
with the principle of the conservation of forces. This quantity of active force, which 
is usually manifested in the form of heat, may be called the interior work of the 
circuit. 
Now suppose the current to act upon bodies external to its own circuit ; we know 
that it may produce currents of induction, magnetization, &c., forces which may 
themselves be converted either into heat or into mechanical work. This new quan- 
tity of active force may be called the exterior work of the circuit. 
If it were to be supposed that nothing was changed in the primary circuit when 
it had to exert an exterior action, that the interior work has its value whether or no 
the current produces exterior work, this would lead us to admit a creation of force, 
and to place ourselves in complete opposition to the fundamental principles of 
mechanics. 
What are the changes into the phenomena produced in the interior of the circuit 
when exterior work is produced? in other words, how is the conversion of force 
then effected? This is the question, the investigation of which I have set before me. 
We are already aware, principally from the researches of M. Jacobi, that when 
mechanical work is produced by means of electricity with the aid of an electro-mag- 
netic machine, the current employed diminishes in intensity ; with this diminution 
of intensity, a diminution of the heat evolved in the circuit must necessarily cor- 
respond. But it appears to me that the explanation is far from being satisfactory. 
In fact, at the same time that the intensity of the current is weakened, the chemical 
action is also weakened ; and according to Faraday’s law, which appears to be now 
well established, it is admitted that the amount of chemical work produced in the 
battery is always proportionate to the intensity of the current. It results from this, 
that, as regards the chemical action, we may perfectly assimilate a current whose 
intensity is weakened because it produces exterior work, with another current which 
exerts no exterior action, but of which the intensity is less. We may therefore 
conceive two circuits, one only producing interior work, the other producing exterior 
work in addition, but having both the same intensity, and consequently consuming 
the same quantity of zinc in the two batteries to which they owe their origin; can 
we suppose that the interior work will be the same in both circuits ? Evidently not; 
this again would be to admit a creation of force. A change, for example, a diminu- 
tion in the heat evolved, must supervene, either in the part of the circuit which 
exerts the exterior action by induction, or in the battery itself; or else Faraday’s 
law ceases to be correct in this case. 
I am far from having arrived at the solution of this question; and for the present 
I must confine myself to the investigation of some of its elements. 
First Memoir.—On the variations of intensity undergone by the electric current 
when it produces mechanical work. 
When an electric current is employed in setting any machine in motion, it under- 
